Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

The FDA is actually straining a bit to gain oversight of this emerging technology.

Technically, the FDA deals with new drugs and medical devices — not animal breeding. But as genetically engineering an animal requires using new genetic tricks to alter DNA, the agency is calling the gene-modifying technology a drug and claiming authority over who does what to design animals. While a court challenge may well be in store, let's hope the FDA wins because some federal agency needs to keep an eye on this powerful but possibly dangerous new way to make the food on your dinner table, the pets in your house and even what you may someday see at a zoo.

Not only does the FDA need to keep an eye on bioengineering, but another question needs to be answered: Should the FDA require products from bioengineered animals to be labeled? There is nothing about labeling in today's plan.

Why go there?
Why should anyone be making genetically engineered animals anyway? Most of the concerns raised about these critters are ethical.

Some argue that it is inherently wrong for us to try and manipulate the heredity of animals. It is not our place to change the essential characteristics of a horse or a chicken. Nor can we be sure, critics worry, that genetically engineered animals will produce milk or meat that is absolutely safe to eat. And some critics worry that mixing genes from different species is not only unnatural but may wind up creating animals who wind up interbreeding with others and making offspring with traits that no one ever intended or anticipated.

These ethical worries are not all legitimate. In a world in which there are thousands of varieties of pigs, chickens, sheep, cows, dogs, cats and mice all made by humans using selective breeding, it is hard to argue that it is inherently wrong to change "the essence" of any animal. We have changed our domestic animals so much that their wild relatives can no longer recognize them. Genetic engineering speeds the process and allows more drastic changes to be undertaken, but it is not fundamentally different than what it took our ancestors a few thousand years to do to get to the Chihuahua, Pekingese, collie or Great Dane.

We also need to be sure that genetically engineered animals are kept confined so that they do not go out and interbreed with other animals spreading traits and behaviors that might not be very desirable. Think about the killer bees that have become such a nuisance, and you will have an idea of what bad things can happen when a newly engineered animal gets out and starts breeding with the locals.

How can we be sure of safety?
As for safety, who knows if genetically engineered pork chops will be any scarier than an American meal, which could consist of a Slim Jim, a Scooter Pie and a Red Bull. Still, it is absolutely essential that what winds up on your dinner table from a genetically engineered pig or duck had better be safe.

Happily, the FDA gets this. The agency is making it clear that it will demand evidence of safety for foods from all genetically engineered animals before they reach your dinner table. And the draft rules say that breeders will have to monitor their animals so that they know exactly where they are and who they might be romancing on any given evening.

Ethically, the benefits of pushing forward with bioengineering seem worth the risk. Creating animals whose manure is less destructive of the environment, as Canadian scientists have already done, or animals whose meat or milk is healthier to eat, as a number of U.S. researchers have done with various animals, or even animals that are more resistant to diseases thereby reducing the need for giving them antibiotics, would be beneficial both for the animals and for us. The world is facing a global shortage of food alongside the need to reduce the environmental burden caused by current farming practices and using our new knowledge of genetics is one ethical way to try and address that problem.

The big question remains: Do you have a right to know if your food comes from a genetically engineered animal?

Even if the FDA says that food is safe, what if you don’t want to eat it?

The FDA is not likely to insist on labeling. If it deems the data on a particular animal product convincing as to its safety, they'll argue, what's the point?

I do think you have a right to know what you are eating or how the pet you are thinking of buying was created. The bioagriculture and food industry should simply agree to label — if not on packages then at least on publicly accessible Web sites.

Arthur Caplan, Ph.D., is director of the Center for Bioethics at the University of Pennsylvania.